/* 
 * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
 * Copyright (c) 2006-2018 Christian Walter <cwalter@embedded-solutions.at>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/* ----------------------- System includes ----------------------------------*/
#include "stdlib.h"
#include "string.h"

#include "../include/mb.h"
#include "../include/mbframe.h"
#include "../include/mbproto.h"
#include "../include/mbconfig.h"


/* ----------------------- Defines ------------------------------------------*/
#define MB_PDU_FUNC_READ_ADDR_OFF               ( MB_PDU_DATA_OFF + 0)
#define MB_PDU_FUNC_READ_REGCNT_OFF             ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_READ_SIZE                   ( 4 )
#define MB_PDU_FUNC_READ_REGCNT_MAX             ( 0x007D )

#define MB_PDU_FUNC_WRITE_ADDR_OFF              ( MB_PDU_DATA_OFF + 0)
#define MB_PDU_FUNC_WRITE_VALUE_OFF             ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_WRITE_SIZE                  ( 4 )

#define MB_PDU_FUNC_WRITE_MUL_ADDR_OFF          ( MB_PDU_DATA_OFF + 0 )
#define MB_PDU_FUNC_WRITE_MUL_REGCNT_OFF        ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_WRITE_MUL_BYTECNT_OFF       ( MB_PDU_DATA_OFF + 4 )
#define MB_PDU_FUNC_WRITE_MUL_VALUES_OFF        ( MB_PDU_DATA_OFF + 5 )
#define MB_PDU_FUNC_WRITE_MUL_SIZE_MIN          ( 5 )
#define MB_PDU_FUNC_WRITE_MUL_REGCNT_MAX        ( 0x0078 )

#define MB_PDU_FUNC_READWRITE_READ_ADDR_OFF     ( MB_PDU_DATA_OFF + 0 )
#define MB_PDU_FUNC_READWRITE_READ_REGCNT_OFF   ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_READWRITE_WRITE_ADDR_OFF    ( MB_PDU_DATA_OFF + 4 )
#define MB_PDU_FUNC_READWRITE_WRITE_REGCNT_OFF  ( MB_PDU_DATA_OFF + 6 )
#define MB_PDU_FUNC_READWRITE_BYTECNT_OFF       ( MB_PDU_DATA_OFF + 8 )
#define MB_PDU_FUNC_READWRITE_WRITE_VALUES_OFF  ( MB_PDU_DATA_OFF + 9 )
#define MB_PDU_FUNC_READWRITE_SIZE_MIN          ( 9 )

/* ----------------------- Static functions ---------------------------------*/
eMBException    prveMBError2Exception( eMBErrorCode eErrorCode );

/* ----------------------- Start implementation -----------------------------*/
#if MB_FUNC_WRITE_HOLDING_ENABLED > 0
eMBException WHT_MB_Func_Write_Holding_Register(uint8_t* pucFrame, uint16_t* usLen)
{
    uint16_t        usRegAddress;
    eMBException    eStatus = MB_EX_NONE;
    eMBErrorCode    eRegStatus;

    if( *usLen == ( MB_PDU_FUNC_WRITE_SIZE + MB_PDU_SIZE_MIN ) )
    {
        usRegAddress = ( uint16_t )( pucFrame[MB_PDU_FUNC_WRITE_ADDR_OFF] << 8 );
        usRegAddress |= ( uint16_t )( pucFrame[MB_PDU_FUNC_WRITE_ADDR_OFF + 1] );
        usRegAddress++;

        /* 进行回调以更新值。 */
        eRegStatus = WHT_MB_RegHolding_Callback(&pucFrame[MB_PDU_FUNC_WRITE_VALUE_OFF], usRegAddress, 1, MB_REG_WRITE);

        /* 如果发生错误，将其转换为Modbus异常。 */
        if( eRegStatus != MB_ENOERR )
        {
            eStatus = prveMBError2Exception( eRegStatus );
        }
    }
    else
    {
        /* 不能成为有效的请求，因为长度不正确。 */
        eStatus = MB_EX_ILLEGAL_DATA_VALUE;
    }
    return eStatus;
}
#endif

#if MB_FUNC_WRITE_MULTIPLE_HOLDING_ENABLED > 0
eMBException WHT_MB_Func_Write_Multiple_Holding_Register( uint8_t * pucFrame, uint16_t * usLen )
{
    uint16_t          usRegAddress;
    uint16_t          usRegCount;
    uint8_t           ucRegByteCount;

    eMBException    eStatus = MB_EX_NONE;
    eMBErrorCode    eRegStatus;

    if( *usLen >= ( MB_PDU_FUNC_WRITE_MUL_SIZE_MIN + MB_PDU_SIZE_MIN ) )
    {
        usRegAddress = ( uint16_t )( pucFrame[MB_PDU_FUNC_WRITE_MUL_ADDR_OFF] << 8 );
        usRegAddress |= ( uint16_t )( pucFrame[MB_PDU_FUNC_WRITE_MUL_ADDR_OFF + 1] );
        usRegAddress++;

        usRegCount = ( uint16_t )( pucFrame[MB_PDU_FUNC_WRITE_MUL_REGCNT_OFF] << 8 );
        usRegCount |= ( uint16_t )( pucFrame[MB_PDU_FUNC_WRITE_MUL_REGCNT_OFF + 1] );

        ucRegByteCount = pucFrame[MB_PDU_FUNC_WRITE_MUL_BYTECNT_OFF];

        if( ( usRegCount >= 1 ) && ( usRegCount <= MB_PDU_FUNC_WRITE_MUL_REGCNT_MAX ) && ( ucRegByteCount == ( uint8_t ) ( 2 * usRegCount ) ) )
        {
            /* 进行回调以更新寄存器值。 */
            eRegStatus = WHT_MB_RegHolding_Callback(&pucFrame[MB_PDU_FUNC_WRITE_MUL_VALUES_OFF], usRegAddress, usRegCount, MB_REG_WRITE);

            /* 如果发生错误，将其转换为Modbus异常。 */
            if( eRegStatus != MB_ENOERR )
            {
                eStatus = prveMBError2Exception( eRegStatus );
            }
            else
            {
                /* 响应包含功能代码、起始地址和寄存器数量。我们重用缓冲区中的旧值，因为它们仍然有效。*/
                *usLen = MB_PDU_FUNC_WRITE_MUL_BYTECNT_OFF;
            }
        }
        else
        {
            eStatus = MB_EX_ILLEGAL_DATA_VALUE;
        }
    }
    else
    {
        /* 这不可能是一个有效的请求，因为长度不正确。 */
        eStatus = MB_EX_ILLEGAL_DATA_VALUE;
    }
    return eStatus;
}
#endif

#if MB_FUNC_READ_HOLDING_ENABLED > 0
eMBException WHT_MB_Func_Read_Holding_Register(uint8_t* pucFrame, uint16_t* usLen)
{
    uint16_t          usRegAddress;
    uint16_t          usRegCount;
    uint8_t          *pucFrameCur;

    eMBException    eStatus = MB_EX_NONE;
    eMBErrorCode    eRegStatus;

    if( *usLen == ( MB_PDU_FUNC_READ_SIZE + MB_PDU_SIZE_MIN ) )
    {
        usRegAddress = ( uint16_t )( pucFrame[MB_PDU_FUNC_READ_ADDR_OFF] << 8 );
        usRegAddress |= ( uint16_t )( pucFrame[MB_PDU_FUNC_READ_ADDR_OFF + 1] );
        usRegAddress++;

        usRegCount = ( uint16_t )( pucFrame[MB_PDU_FUNC_READ_REGCNT_OFF] << 8 );
        usRegCount = ( uint16_t )( pucFrame[MB_PDU_FUNC_READ_REGCNT_OFF + 1] );

        /* 检查要读取的寄存器数量是否有效。如果无效，返回Modbus非法数据值异常。*/
        if( ( usRegCount >= 1 ) && ( usRegCount <= MB_PDU_FUNC_READ_REGCNT_MAX ) )
        {
            /* 将当前PDU数据指针设置到起始位置。 */
            pucFrameCur = &pucFrame[MB_PDU_FUNC_OFF];
            *usLen = MB_PDU_FUNC_OFF;

            /* 第一个字节包含功能代码。 */
            *pucFrameCur++ = MB_FUNC_READ_HOLDING_REGISTER;
            *usLen += 1;

            /* 响应中的第二个字节包含字节数。 */
            *pucFrameCur++ = ( uint8_t ) ( usRegCount * 2 );
            *usLen += 1;

            /* 进行回调以填充缓冲区。 */
            eRegStatus = WHT_MB_RegHolding_Callback(pucFrameCur, usRegAddress, usRegCount, MB_REG_READ);
            /* 如果发生错误，将其转换为Modbus异常。 */
            if( eRegStatus != MB_ENOERR )
            {
                eStatus = prveMBError2Exception( eRegStatus );
            }
            else
            {
                *usLen += usRegCount * 2;
            }
        }
        else
        {
            eStatus = MB_EX_ILLEGAL_DATA_VALUE;
        }
    }
    else
    {
        /* 这不可能是一个有效的请求，因为长度不正确。 */
        eStatus = MB_EX_ILLEGAL_DATA_VALUE;
    }
    return eStatus;
}
#endif

#if MB_FUNC_READWRITE_HOLDING_ENABLED > 0
eMBException WHT_MB_Func_Read_Write_Multiple_Holding_Register(uint8_t* pucFrame, uint16_t* usLen)
{
    uint16_t          usRegReadAddress;
    uint16_t          usRegReadCount;
    uint16_t          usRegWriteAddress;
    uint16_t          usRegWriteCount;
    uint8_t           ucRegWriteByteCount;
    uint8_t          *pucFrameCur;

    eMBException    eStatus = MB_EX_NONE;
    eMBErrorCode    eRegStatus;

    if( *usLen >= ( MB_PDU_FUNC_READWRITE_SIZE_MIN + MB_PDU_SIZE_MIN ) )
    {
        usRegReadAddress = ( uint16_t )( pucFrame[MB_PDU_FUNC_READWRITE_READ_ADDR_OFF] << 8U );
        usRegReadAddress |= ( uint16_t )( pucFrame[MB_PDU_FUNC_READWRITE_READ_ADDR_OFF + 1] );
        usRegReadAddress++;

        usRegReadCount = ( uint16_t )( pucFrame[MB_PDU_FUNC_READWRITE_READ_REGCNT_OFF] << 8U );
        usRegReadCount |= ( uint16_t )( pucFrame[MB_PDU_FUNC_READWRITE_READ_REGCNT_OFF + 1] );

        usRegWriteAddress = ( uint16_t )( pucFrame[MB_PDU_FUNC_READWRITE_WRITE_ADDR_OFF] << 8U );
        usRegWriteAddress |= ( uint16_t )( pucFrame[MB_PDU_FUNC_READWRITE_WRITE_ADDR_OFF + 1] );
        usRegWriteAddress++;

        usRegWriteCount = ( uint16_t )( pucFrame[MB_PDU_FUNC_READWRITE_WRITE_REGCNT_OFF] << 8U );
        usRegWriteCount |= ( uint16_t )( pucFrame[MB_PDU_FUNC_READWRITE_WRITE_REGCNT_OFF + 1] );

        ucRegWriteByteCount = pucFrame[MB_PDU_FUNC_READWRITE_BYTECNT_OFF];

        if( ( usRegReadCount >= 1 ) && ( usRegReadCount <= 0x7D ) &&
            ( usRegWriteCount >= 1 ) && ( usRegWriteCount <= 0x79 ) &&
            ( ( 2 * usRegWriteCount ) == ucRegWriteByteCount ) )
        {
            /* 进行回调以更新寄存器值。 */
            eRegStatus = WHT_MB_RegHolding_Callback(&pucFrame[MB_PDU_FUNC_READWRITE_WRITE_VALUES_OFF], usRegWriteAddress, usRegWriteCount, MB_REG_WRITE);

            if( eRegStatus == MB_ENOERR )
            {
                /* 将当前的PDU数据指针设置到起始位置。 */
                pucFrameCur = &pucFrame[MB_PDU_FUNC_OFF];
                *usLen = MB_PDU_FUNC_OFF;

                /* 第一个字节包含功能代码。 */
                *pucFrameCur++ = MB_FUNC_READWRITE_MULTIPLE_REGISTERS;
                *usLen += 1;

                /* 响应中的第二个字节包含字节数。 */
                *pucFrameCur++ = ( uint8_t ) ( usRegReadCount * 2 );
                *usLen += 1;

                /* 创建读取回调函数。 */
                eRegStatus = WHT_MB_RegHolding_Callback(pucFrameCur, usRegReadAddress, usRegReadCount, MB_REG_READ);
                if( eRegStatus == MB_ENOERR )
                {
                    *usLen += 2 * usRegReadCount;
                }
            }
            if( eRegStatus != MB_ENOERR )
            {
                eStatus = prveMBError2Exception( eRegStatus );
            }
        }
        else
        {
            eStatus = MB_EX_ILLEGAL_DATA_VALUE;
        }
    }
    return eStatus;
}
#endif
